Thyroid cancer, or cancer of the thyroid is cancer of the thyroid gland, which is located in the front of the neck – the thyroid gland produces hormones which regulate normal body metabolism, heart rate, blood pressure, body temperature and weight. It is not a common type of cancer, although its incidence is rising.
There are various types of thyroid cancer:
- Papillary thyroid cancer – accounts for about 80% of all cases. It is most commonly diagnosed in patients aged between 30 and 50 years of age.
- Follicular thyroid cancer – accounts for about 11% of all cases. It is most commonly diagnosed in individuals aged 50 years or more.
- Medullary thyroid cancer – accounts for about 4% of all cases. Some patients have a genetic fault (mutation) and commonly have cancer in other glands as well.
- Anaplastic thyroid cancer – accounts for about 1% or 2% of all cases. It is most commonly diagnosed in patients over 60 years of age. It is an aggressive cancer.
- Thyroid lymphoma – accounts for about 1% to 2% of all cases. This rare cancer typically affects patients aged over 70 years. It begins in the immune system cells in the thyroid gland.
Medullary, anaplastic and thyroid lymphoma are usually more aggressive and more likely to spread.
Thyroid cancer affects both men and women, but women are more likely to get it (75% of all cases).
According to the CDC (Centers for Disease Control and Prevention), USA, approximately 37,000 Americans are diagnosed with thyroid cancer annually. The National Health Service (NHS), UK, informs that thyroid cancer accounts for about 1% of all cancers diagnosed in the United Kingdom. In England and Wales (not including Scotland or Northern Ireland) approximately 1,200 new cases are diagnosed each year.
What are the causes of thyroid cancer?
What is cancer? – cancer is a class of diseases characterized by out-of-control cell growth. Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.
More dangerous, or malignant, tumors form when two things occur:
- a cancerous cell manages to move throughout the body using the blood or lymph systems, destroying healthy tissue in a process called invasion
- that cell manages to divide and grow, making new blood vessels to feed itself in a process called angiogenesis.
When a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues, it is said to have metastasized. This process itself is called metastasis, and the result is a serious condition that is very difficult to treat.
In 2007, cancer claimed the lives of about 7.6 million people in the world. Physicians and researchers who specialize in the study, diagnosis, treatment, and prevention of cancer are called oncologists.
Cancer is ultimately the result of cells that uncontrollably grow and do not die. Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer begins to form. Unlike regular cells, cancer cells do not experience programmatic death and instead continue to grow and divide. This leads to a mass of abnormal cells that grows out of control.
Papillary and follicular thyroid cancers spread much more slowly than the other, rarer types.